Jenson Button of McLaren and Red Bull's Mark Webber were next just over a half-second behind.

Ferrari are without a win after seven races and have suggested they might turn their attention to the 2012 season unless results improve soon.

Fifth and adrift

Alonso admitted frustration on Thursday over the Italian team's failure to get closer to Red Bull despite the two-time world champion saying he's never driven better. Alonso has two podium finishes but is 92 points behind Vettel in fifth.

But despite the strong practice session, Alonso said he doesn't expect to be in front after Saturday's qualifying.

"We can't think that a magical potion will suddenly appear tomorrow. Red Bull has won every pole this season and McLaren has also done better than us in qualifying this year," two-time world champion Alonso said.

"We can't think that a magical potion will suddenly appear tomorrow. Red Bull has won every pole this season and McLaren has also done better than us in qualifying"

Ferrari's Fernando Alonso

"Overtaking is difficult here but not impossible, so it's important to start in the front."

Vettel leads Button by 60 points going into Sunday's race, with the German driver having won five of seven GPs this season. Red Bull has also started from pole in every race.

"It was very tight with the times, but I had a very good feeling in the car," said Vettel, who finished 16th in the morning as he ran experimental setups with the upcoming British GP in mind.

Webber, who is next in the standings in front of Hamilton, had topped the first practice session with a time more than two seconds slower.

Button, coming off a dramatic last-lap victory over Vettel in Montreal, said McLaren was struggling to adapt its car to a medium tire compound just introduced for the race.

"It's difficult to get both tires working similarly with the same setup," Button said, adding that it makes it difficult to predict what McLaren's chances are of taking pole on Saturday.

"I haven't got a clue," he said.

Road to recovery

Sauber driver Sergio Perez completed both practice sessions to suggest the Mexican rookie would be available to race after missing the Canadian GP as he recovered from a heavy crash in Monaco.

"It's going to be very tough to come back this weekend at a race that is so physically demanding," said Perez, who was 16th, 2.552 seconds behind Alonso.

The two 90-minute sessions were mostly free of incident with the exception of Niko Hulkenberg swerving into the wall at the end of the main straight to exit early in the first session.

The slippery track and addition of the new tires provided problems for many drivers at the same spot as Hulkenberg's crash, but most were able to recover and escape into the run-off area when in danger.

"You just slide, the car just oversteers - it's like rallying," Hamilton said.

"Then you put the option tire on and it's so much more stable - it's almost like it goes from being on a skid pan to being on train tracks."

Content on this website is for general information purposes only. Your comments
are provided by your own free will and you take sole responsibility for any direct
or indirect liability. You hereby provide us with an irrevocable, unlimited, and
global license for no consideration to use, reuse, delete or publish comments, in
accordance with Community Rules & Guidelines and Terms and Conditions.